main(a)

any very large body of (salt) water

同义词：briny

a principal pipe in a system that distributes water or gas or electricity or that collects sewage adj.
most important element

"the main doors were of solid glass"

同义词：chief(a)primary(a)principal(a)

(of a clause) capable of standing syntactically alone as a complete sentence

"the main (or independent) clause in a complex sentence has at least a subject and a verb"

同义词：independent

of force; of the greatest possible intensity

"by main strength"